1. Field of the Invention
This invention is directed to a process for melt blending a particular polyamide. The process involves an improvement to the melt blending of poly(4,7-dioxadecamethylene adipamide), hereinafter referred to as N-30203-6, and nylon-6 (also polycaprolactam), hereinafter referred to as N-6. The improved process results in a block copolymer, poly(4,7-dioxadecamethylene adipamide)-polycaprolactam, hereinafter referred to as N-30203-6//6, having enhanced properties.
2. Description of the Prior Art
The block copolymer N-30203-6//6 and method for preparing for it, are disclosed in R. M. Thompson's copending U.S. application Ser. No. 557,717, filed Mar. 12, 1975. One method of preparing N-30203-6//6 and other such copolymers is known as melt blending. The block copolymer has utility as a hydrophilic fiber. However, it can have a fusion problem described hereinafter.
To form a fabric from N-30203-6//6 the copolymer is spun into a fiber by known means. While spinning the fiber, a lubricating finish is applied to the fiber to facilitate subsequent processing steps. After the copolymer is spun, it is drawn and then annealed to stabilize the drawing. The resulting fiber is knitted into a tube and then, to wash off the finish applied earlier, it is placed in boiling water. During this washing off in the boiling water, which is also known as scouring, the copolymer fibers have a tendency to fuse together. This fusion causes the knitted fabric to become stiff which is unacceptable to a wearer.